Method of enhancing fracture conductivity

Patent metadata

Field	Value
Publication number	US-9429006-B2
Application number	US-201414285355-A
Country	US
Kind code	B2
Filing date	May 22, 2014
Priority date	Mar 1, 2013
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

The method includes the introduction of a proppant-free stage and a proppant laden stage into the wellbore and/or subterranean formation. The method increases the effective fracture width and enhances fracture conductivity within the formation. Either the proppant-free stage or the proppant laden stage contains a breaker. At least one of the proppant-free stage or proppant laden stage contains a viscosifying agent to which the breaker has affinity. The viscosifying agent may be a superabsorbent, a viscosifying polymer (other than a superabsorbent) or a viscoelastic surfactant. The breaker has greater affinity for the viscosifying agent not present in the same stage as the breaker. Either the proppant-free stage or the proppant laden stage may be foamed.

First claim

We claim:

1. A method of hydraulically fracturing a subterranean formation comprising:
pumping into the formation at least two stages wherein a first stage is a proppant-free and a second stage is a proppant laden wherein:
(a) either the first stage or second stage contains a breaker;
(b) each of the stages contains at least one viscosifying agent, wherein the viscosifying agent is a superabsorbent polymer, a synthetic polymer or a viscoelastic surfactant and further wherein (i) the synthetic polymer is other than a superabsorbent polymer; (ii) at least one of the stages contains at least one superabsorbent polymer; and (iii) the breaker has less affinity for the viscosifying agent in the stage containing the breaker than the viscosifying agent of the other stage; and
degrading the viscosifying agent in the stage not containing the breaker with the breaker at in-situ reservoir conditions.

2. The method of claim 1 , wherein the first stage, second stage or both the first stage and second stage contain a friction reduction polymer and wherein the breaker has less affinity for the friction reduction polymer than the viscosifying agent.

3. The method of claim 1 , wherein the viscosifying agent is a synthetic polymer.

4. The method of claim 3 , wherein the synthetic polymer is a polyvinyl alcohol, polyacrylate, poly(meth)acrylate, polyvinylpyrrolidone, polyacrylamide, poly(meth)arylamide, polyethylene oxide, a copolymer of vinyl alcohol, acrylic acid, (meth)arylic acid, acrylamide, (meth)acrylamide, acrylamidomethylpropane sulfonic acid (AMPS), a salt of (AMPs), maleic anhydride methyl vinyl ether or a derivative thereof.

5. The method of claim 4 , wherein the synthetic polymer is a copolymer of acrylamide, an acrylate and an AMPS.

6. The method of claim 1 , wherein the viscosifying agent is a superabsorbent polymer.

7. The method of claim 6 , wherein the superabsorbent polymer is a starch-grafted polyacrylate, acrylamide/acrylic acid copolymer, starch-grafted acrylamide/acrylic acid; starch-acrylonitrile graft copolymers; homopolymer of polyacrylonitrile; isobutylene/maleic anhydride copolymers; chitosan/polyvinylpyrrolidone; or a chitosan/polyethyleneimine or a salt thereof and mixtures thereof.

8. The method of claim 6 , wherein the superabsorbent is a copolymer of an acrylic acid, (meth)acrylic acid, acrylate, (meth)acrylate, acrylamide, (meth)acrylamide, vinylpyrrolidone, vinyl acetate, ethylene glycol, acrylonitrile, methacrylonitrile, N-vinylformamide, N-vinylacetamide, vinyl alcohol, vinyl acetate, allyl alcohol, maleic acid, maleic anhydride, fumaric acid, itaconic acid, β-acryloyloxypropionic acid, sorbic acid, α-chlorosorbic acid, 2′-methylisocrotonic acid, cinnamic acid, p-chlorocinnamic acid, β-stearyl acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, 2-acrylamido-2-methylpropanesulfonic acid, allyl sulfonic acid, vinyl sulfonic acid, allyl phosphonic acid, vinyl phosphonic acid, acrylamidopropyl trimethyl ammonium chloride and derivatives thereof.

9. The method of claim 8 , wherein the superabsorbent is a copolymer of a hydroxyethyl acrylate, hydroxyethyl(meth)acrylate, acrylamide and maleic anhydride, an alkyl-substituted acrylamide, aminoalkyl-substituted acrylamide derivative, alkyl substituted derivative of methacrylamide, aminoalkyl-substituted acrylamide derivative, or a combination thereof ethacrylic acid, α-chloroacrylic acid, β-cyanoacrylic acid, β-methylacrylic acid (crotonic acid), α-phenylacrylic acid, N,N-di-C 1 -C 8 alkylamino-C 1 -C 8 alkylacrylate and diallyldimethyl ammonium chloride and mixtures thereof.

10. The method of claim 6 , wherein the proppant of the proppant laden slurry is disposed in the superabsorbent polymer and further wherein the proppant is released upon breaking of the superabsorbent polymer at in-situ conditions.

11. The method of claim 1 , wherein the breaker is at least one enzyme or oxidative breaker.

12. The method of claim 1 , wherein the proppant laden slurry is introduced into the formation at a concentration sufficient to achieve a partial monolayer propped fracture and further wherein a partial monolayer propped fracture is created in the formation.

13. The method of claim 1 , wherein either the first stage or the second stage or both the first stage and the second stage are foamed.

14. A method of hydraulically fracturing a subterranean formation comprising pumping into the formation at least two stages wherein a first stage is proppant-free and a second stage is proppant laden and further wherein (i) one of the stages contains at least one superabsorbent polymer and the other stage contains a breaker; (ii) either the first stage or the second stage optionally contains a friction reduction agent; and (iii) the breaker has greater affinity for the superabsorbent polymer than the optional friction reduction agent.

15. The method of claim 14 , wherein a filter cake is deposited onto the fracture face of the subterranean formation, the filter cake being composed at least in part by the at least one superabsorbent polymer and further wherein the at least one breaker degrades at least a portion of the filter cake.

16. The method of claim 14 , wherein the proppant laden stage contains slickwater.

17. A method of hydraulically fracturing a subterranean formation comprising pumping into the formation at least two stages wherein a first stage is proppant-free and a second stage is proppant laden and further wherein:
(a) at least one of the stages contains at least one first viscosifying agent and the other stage contains a breaker and optionally a second viscosifying agent;
(b) the at least one first viscosifying agent and optional second viscosifying agent are independently selected from the group consisting of a superabsorbent polymer, a viscosifying polymer and a viscoelastic surfactant, wherein the viscosifying polymer is other than a superabsorbent polymer;
(c) at least one of the first stage or second stage is foamed; and
(d) the breaker has less affinity for the optional second viscosifying agent than the at least one first viscosifying agent.

18. The method of claim 17 , wherein both stages are foamed.

19. The method of claim 17 , wherein the least one of the first stage or second stage is foamed with nitrogen, carbon dioxide, natural gas or a combination thereof.

20. The method of claim 17 , wherein the foamed stage is the proppant laden stage.

21. The method of claim 17 , wherein the foamed stage is the proppant-free stage.

22. The method of claim 17 , wherein both the proppant laden stage and the proppant-free stage are foamed.

23. The method of claim 17 , wherein each of the proppant laden stage and the proppant-free stage contain at least one viscosifying agent.

24. The method of claim 17 , wherein either the first stage, the second stage or both the first stage and second stage contain a friction reduction agent and further wherein the breaker has less affinity for the friction reduction agent than the at least one viscosifying agent.

25. The method of claim 17 , wherein a filter cake is deposited onto the fracture face of the subterranean formation, the filter cake being composed at least in part by the at least one viscosifying agent and further wherein the at least one breaker degrades at least a portion of the filter cake.

26. The method of claim 17 , wherein the proppant laden stage contains slickwater.

Assignees

• Brannon Harold Dean
• Ward Brian N
• Gupta D V Satyanarayana
• Nelson Scott Gregory
• Baker Hughes Inc

Inventors

• Brannon Harold Dean
• Ward Brian N
• Gupta D V Satyanarayana
• Nelson Scott Gregory

Classifications

• C09K2208/26

  Gel breakers other than bacteria or enzymes · CPC title

• C09K8/68 Primary

  containing organic compounds · CPC title

• C09K2208/30

  Viscoelastic surfactants [VES] · CPC title

• C09K2208/24

  Bacteria or enzyme containing gel breakers · CPC title

• E21B43/267 Primary

  reinforcing fractures by propping · CPC title